微通道板对软X射线响应的实验研究

在X光成像望远镜中微通道板(MCP)作为焦平面上的成像接收器,探测天体的软X射线辐射图像。本文实验研究在软X射线波段MCP的成像性能以及与此有关的其他性能。作者没计了实验装置,测量了在碳K_a(4.47nm)线下微通道板——荧光屏组件的分辨率,与计算结果进行了比较。提出了一种用软X射线光电发射作为初电流测量MCP电流增益的新方法,具有可反复多次测量、重复性良好及测量方便等优点。测量了在两个波长下微通道板的量子效率及随X射线入射角的变化。     

IBMPC微计算机中被误删除文件的恢复

本文提出了恢复IBM PC/XT和PC/AT中,被误删除文件的恢复方法。指出了文件能够完全恢复或部分恢复的条件。用例子说明了软磁盘和硬磁盘上恢复文件的具体步骤。     

光折变晶体两波耦合增益系数强度特性理论研究

对两中心模型光折变晶体两波耦合增益系数Γ,总的有效陷阱密度N_eff和强度特性因子η(I)的强度特性进行了理论研究。结果显示在两中心模型的光折变晶体中,Γ,N_eff和η(I)有着复杂的特性。当S_Dγ_T/S_Tγ_D小时,对于A类和B类两中心晶体,N_eff随强度的增加而增加最终趋于饱和,当S_Dγ_T/S_Tγ_D大时,对于A类晶体N_eff增加到一个最大值后稍有减少,而对于B类晶体,N_eff增加到最大值后然而有较大的减少。不同类型晶体增益系数Γ有着不同的强度特性是由于晶体中有着不同的能级结构。     

合成孔径雷达光学处理器的功能和成像质量的检测

合成孔径雷达光学处理器(OSARP)与普通成像系统不同,它处理合成孔径雷达(SAR),数据片.因此,我们不仅要检测OSARP的成像质量还要检测它的功能.本文提供一种检测OSARP的方法.OSARP的功能是通过检测OSARP各组件的调整量来求得的;OSARP的成像质量是用普通检测靶加位移透镜来检测的.我们使用模拟SAR效据片来检验OSARP处理各种雷达相位历程的能力.最后用真实SAR数据片来检验SAR和OSARP的综合成像质量.用这种方法我们实地检测HG-1型OSARP,实测结果表明这种检测方法是可行的.     

改进型Wollaston棱镜设计

介绍了改进型Wollaston棱镜的特点、主要参数及基于这些参数对光学系统结构的设计公式。应用Matlab软件自编程序对分束角ε与棱镜楔角γ和光轴倾角δ之间,相干平面倾角η与棱镜楔角γ和光轴倾角δ之间的关系进行了计算并对结果做了分析,得出一些有实用价值的结论,克服了Wollaston棱镜使用上的局限,因而扩大了它的应用范围。     

软X射线光学技术的某些进展

本文主要介绍软X射线等离子体光源、多层膜软X射线反射镜和软X射线显微镜。高强度的实验室用软X射线等离子体光源较之同步辐射具有体积小、造价低、光束大和单位脉冲光通量高等优点。最近发展的多层镀膜用于软X射线正入射光学元件,可以得到比掠入射光学元件好得多的分辨率。软X射线显微镜提供了生物样品分析的一种新工具,它填补了常用的光学显微镜和电子显微镜之间的空隙。     

简化逻辑设计的一种新方法——解布尔方程法

本文讨论了简化 f(A₁,…,A_n)=1的逻辑设计一种新方法.此方法为:解出满足 f(A₁,…,A_n)=1=0的关系表达式组.然后,设计出实现此关系表达式组的逻辑线路,此线路与实现 f(A₁,…,A_n)=1的逻辑线路等价.     

IBM PC/XT对TP801-A的控制与管理

本文介绍IBM PC/XT个人计算机和TP801—A单板机的一种联机方法及其控制与管理技巧.     

HTF对r、d、n、δ、△N微分的计算

本文推导了传递函数MTF对结构参数r、d、n的微分计算公式,给出了MTF对偏心差δ和局部光圈△N的微分表达式,这些对于以MTF为性能指标,优化求解公差和光学自动设计,都是很有用处的。     

固溶及时效温度对TC18 组织性能的影响

固溶及时效处理是实现钛合金强化的关键工艺,文中采用不同的固溶及时效温度对TC18钛合金进行了强化处理,对处理后合金的显微组织和性能进行了对比分析。在固溶过程中,随着温度的升高,亚稳β相生成量增加,使得后续时效过程的次生α相析出量增加,从而提高了合金强度,但塑性降低;在时效过程中,随着温度的升高,初生α相晶粒长大,次生α相析出量减少,合金强化效果降低而塑性提高。通过控制固溶及时效温度,调整初生α相与次生α相之间的数量及尺寸关系,可以达到调整合金性能的目的。     

Design and performance of a thermal actuator driving a preloaded linear translation stage

A thermally actuated, single-axis, bidirectional translation stage is designed and constructed. To increase the temperature of the thermal actuator, induction heating is used while air-water-mist cooling is used to decrease the temperature. An automated control strategy comprising PID closed loop control (for heating) and On/Off switching between air and mist control (for cooling) is described. The translation stage of this study produces a displacement range of 100 μm and 200 μm (using 240 W and 480 W power sources) in the presence of preloads up to 1 kN. Dependent on the power source used, the root mean square (rms) controller error at steady-state is within 15 nm (240 W) and 35 nm (480 W). No significant variation in the rms controller error was measured in the presence of the different preloads. Dynamic performance is evaluated from step responses over the full range of the actuator as well closed-loop frequency responses. The non-linear, asymmetric aspects of heating and cooling are discussed. Further observations of the system behavior and the preload effect are presented with discussion covering the slew rate, magnitude of overshoot, and controller settling time.     

A prototyping and microfabrication CAD/CAM tool for the excimer laser micromachining process

A CAD/CAM tool for prototyping and small-scale production of micro-electro-mechanical systems (MEMS) devices based on the excimer laser ablation process has been developed. The system’s algorithms use the 3D geometry of a microstructure, defined as an STL file exported from a CAD model, and parameters that influence the process (laser fluence, pulse repetition frequency, number of shots per area, wall angle, stitching errors) to automatically generate a precise NC part program for the excimer laser machine. The performance of the system has been verified by NC part program generation for several 3D microstructures and subsequent machining trials. An initial stitching error of 23.4±2.2-μm wide and 3.4±1.5-μm high was observed when the overlap size between adjacent volumes was zero, when ablating 100×100-μm features in polycarbonate (PC) at a fluence of 0.5 J/cm² using a workpiece-dragging technique. When the size of the overlap was optimised by a system based on optimal process parameters determined by the Taguchi design of experiment method (DOE), and incorporated in the mask design, the maximum stitching error was reduced to 13.4±2.2-μm wide and 1.4±0.9-μm high under the same conditions. By employing a hexagonal-shaped mask with incorporated size of the image overlap, reduced horizontal-stitching errors of 2.4±0.2-μm wide and 1.4±0.2-μm high were observed. The system simplifies part program creation and is useful for excimer laser operators who currently use a tedious trial and error process to create programs and complex masks to generate microstructure parts.     

微机械系统中精密弹性微动工作台的研制及其精度分析

研制了一种低成本、高精度的双层精密弹性微动工作台及其闭环控制系统，并对其精度进行了分析。试验结果表明其分辨力优于０．１μｍ，定位精度优于±０．５μｍ，可作为一般微机械系统中的精密工作台。     

工程表面粗糙度两用测量系统

介绍了一种新型工程表面粗糙度两用测量系统的设计原理、仪器结构及测试结果。该系统可采用接触法和非接触法两种测量方式,接触法测量范围达±１００μｍ,最小分辨率为０．００５μｍ;非接触法测量范围达±２５０μｍ,最小分辨率为０．０１μｍ。     

基因测序仪运动平台的高精度定位控制

为了实现对基因测序仪运动平台的高精度定位控制,建立了基因测序仪运动平台控制系统。对该系统所采用的数学建模、模型辨识、控制器设计、输入整形等方法进行研究。根据运动平台动力学方程和永磁同步直线电机电压-推力关系构建了运动平台数学模型,利用频域扫描法在实物实验的基础上辨识出运动平台的模型参数。最后,基于运动平台模型设计了双闭环控制器和前馈控制器组成的复合控制器来保证运动平台的稳定性和高精度,同时根据整个系统的主导极点设计了输入整形器以抑制运动平台的残余振荡。实验结果表明:加入了输入整形的复合控制器将运动平台的稳态重复定位精度从±1.47μm提高到±0.354μm。较传统复合控制器,本文提出的方法能使基因测序仪运动平台更快进入可用重复定位精度范围,并基本满足基因测序仪采集图像时所需的稳定性强、精度高等要求。     

基于ARM与μCOS-Ⅱ的试验机控制系统设计与研究

针对目前很多试验机控制系统以MS51系列为CPU、以单速度闭环为控制系统的现状,设计了以CortexM3核CPU为硬件平台、以μCOS-II为操作系统的双闭环模糊PID控制系统。介绍了系统的硬件构成,研究了位置闭环和速度闭环自动切换的双闭环控制,给出了系统的测试结果。结果表明,使用该系统的试验机在加载和保载时都有良好的效果。     

Parallel-kinematics XYZ MEMS part 2: Fabrication and experimental characterization

This paper, the second of a set of two papers addressing parallel-kinematics MEMS stages for spatial translation, deals with fabrication, characterization and control of such devices. Double device layer SOI (silicon-on-insulator) substrates are used, providing three layers (two device layers and the handle) into which the elements of the stage can be mapped. Using the mechanism concept, realization scheme, and kinematic and dynamic models developed in the first paper of this set, this paper provides a detailed approach to fabricating these devices. The stages fabricated have a workspace cube of roughly 20 μm on the side, an in-plane stiffness of 96 N/m, and an out-of-plane stiffness of 166 N/m. Further, it characterizes the performance of the individual actuating and sensing elements, configures feedback controllers for each actuated joint, and assesses and verifies the stage’s designed performance. Finally, it demonstrates full 3-axis, closed-loop positioning of a MEMS stage.     

自聚焦伺服的激光测微技术

以激光ＣＤ 光学头为基础,提出新颖的自聚焦伺服测微工作原理,并以此原理试制测微仪。利用半导体激光器作光源,ＣＤ 光学头作高精度位移检测传感器,并利用高分辨率、高动态响应的压电晶体作微位移驱动源,建立实时闭环反馈的自聚焦伺服系统,由单片机进行控制,实现自动跟踪测量。系统首先在±５００μｍ 范围内进行寻焦搜索,实现光学头聚焦于被测表面,随后立即进入闭环聚焦伺服状态,对微位移进行检测。可获得±０．１μｍ 以上的测量精度,测量范围±１０μｍ ,测量形式为非接触测量。同时,该测微仪还有成本低、体积小、使用方便等优点,是一种值得推广的新方法。     

Non-contact measurement methods for micro- and meso-scale tool positioning

The demand for manufacturing microscale components for applications in electronic, biological, and microtool industries has resulted in a reduction in the overall size of machine tools. This trend has motivated the development of new measurement techniques to accurately determine the position of the tool. In this study, two noncontact methods to control the initial position of micro- and meso-scale tools and trace the tool position are described: a laser-based measurement system and a halogen lamp-based measurement system. To evaluate the feasibility of these measurement systems, the prototype per each measurement has been constructed. The laser-based measurement system had a positioning error of ±4.5 μm and the halogen lamp-based measurement system had a positioning error of ±2 μm. Several experiments and simulations were performed to identify the effects of a range of factors likely to be encountered in real-world situations.     

System design of Maxwell force driving fast tool servos based on model analysis

A prototype of the Maxwell force driving fast tool servo (M-FTS) is designed and developed. The M-FTS is capable of accurately translating the cutting tool on a diamond turning machine. The FTS utilizes a flexure-based mechanism driven by Maxwell force to generate movements, a custom linear power amplifier to drive the armature, and a capacitance feedback system to measure accurate displacement. This paper describes the design of electromagnetic circuit, mechanical structures, and controller. The kinematic model of M-FTS is derived to instruct the designs; high-frequency electromagnetic finite element analysis is accomplished to assure the proper driving frequency ranges, and mechanical structure is analyzed to verify the proper displacement and stiffness of mechanical structure. Custom linear power amplifier with a bandwidth of 200 kHz is designed for the M-FTS. According to the experiment results, the frequency response of M-FTS system can be up to 100 kHz when it is open-loop driven. M-FTS has obtained a stroke of 35.5 μm with an open-loop driving. M-FTS can realize a stroke of 11.3 μm and frequency response of 3 kHz with the closed-loop control.